Training Paces Explained: The Five Zones and Why Most Miles Should Be Easy¶

If you only change one thing about how you train, make it this: slow down your easy runs. Running easy days too hard is the most common mistake I see, and it's the one that quietly wrecks the most training. The fix starts with knowing your actual paces — not the ones you wish you could hold.

This is where VDOT comes in.

What VDOT actually is¶

VDOT is Jack Daniels' single number for your current running fitness. You give it one race result, and it works backward to estimate your aerobic capacity and the velocity you can sustain at different efforts. It's not your VO2max from a lab — it's a practical proxy that's been validated against decades of real race data.

The useful part isn't the number itself. It's that one VDOT score sets all of your training paces at once, in proportion to each other. A higher VDOT shifts every zone faster; a lower one slows them all down. You don't guess at each pace separately — they come as a set.

The five zones¶

Daniels splits training into five intensities. Each one trains something different, and each one has a pace.

Easy (E). Conversational. This is where the large majority of your weekly mileage should live — recovery runs, long runs, general aerobic work. Easy running builds the engine: more capillaries, more mitochondria, a stronger heart. If you can't hold a conversation, you're going too fast.

Marathon (M). Steady, controlled, the effort you'd hold for a marathon. Useful for goal-pace work if you're racing long, but it's a small slice of training for most people.

Threshold (T). Comfortably hard. This is tempo pace — the effort you could hold for about an hour all-out. Threshold work raises the point at which fatigue starts cascading, which is one of the highest-return sessions in distance running.

Interval (I). Hard. Three-to-five-minute reps that push your VO2max. This hurts, and it's supposed to. A little goes a long way.

Repetition (R). Fast and short. Reps for speed, running economy, and form. Not about aerobic fitness — about teaching your legs to turn over efficiently.

Why most miles should be Easy¶

Here's the part people resist: roughly 80% of your running should be Easy. The hard zones get the glory, but they only work if you're recovered enough to hit them. Run your easy days at a moderate slog and you arrive at your real workouts already tired — so the hard days aren't hard enough and the easy days aren't easy enough. You end up training in a gray zone that's too hard to recover from and too soft to drive adaptation.

Easy days easy, hard days hard. That polarized structure is what lets the threshold and interval work actually do its job.

How to get your paces from one race¶

You don't need a lab or a fitness test. A recent race — a 5K, a 10K, a half, whatever you've raced honestly in the last month or so — is enough. Plug the distance and finish time into a VDOT calculator and it returns all five zones at once.

That's exactly what the Training Pace Calculator does. Enter one race, get your VDOT score and your E/M/T/I/R paces in seconds. Free, no signup.

One caveat: a single race is a snapshot. It's accurate the day you ran it, but your fitness moves — and so should your paces. As you get fitter, paces from a two-month-old 10K will be too slow. As you fade through a hard block or come back from time off, they'll be too fast.

That's the gap NavRun closes. Connect Strava and it reads your actual training — your long runs, your tempo work, your weekly volume — and keeps your paces current as your fitness changes, then builds them into real weekly plans. No re-racing required to know where you stand.

Start with the calculator. If you want paces that stay honest week to week, connect Strava and let NavRun do it for you.